Microsoft already has OneDrive, but it is not afraid of partnering with Dropbox with the goal of increasing Office 365 subscriptions in mind.

The seemingly surprising partnership between the two companies offering a similar product is not actually very surprising at all. On the face of it, Microsoft appears to be killing off its OneDrive cloud storage service while bolstering its competition.

This is all part of Microsoft CEO Satya Nadella's grander strategy of going where the consumers are and providing products and services across various platforms instead of restricting them all to Windows.

In a blog post, Dropbox head of product Ilya Fushman says that more than 35 billion files uploaded to Dropbox and Dropbox for Business consist of Word, Excel or PowerPoint files, while 1.2 billion people around the world use Office to edit their files.

The move combines both services to allow users to access and work on their files across devices and platforms, and users will be able to link their Word, Excel and PowerPoint apps to their Dropbox accounts "in the next few weeks."

The update will allow users to open their Office files directly in Dropbox and save those files on Dropbox cloud storage, which becomes a default storage option alongside OneDrive.

Users will also be able to open Dropbox from the Office apps and share new or edited files via a Dropbox sharing functionality built right into Office. For users who have Dropbox but no Office, Dropbox will also start pushing users to download Office apps so they can edit their files.

"In our mobile-first and cloud-first world, people need easier ways to create, share and collaborate regardless of their device or platform," says Nadella. "Together, Microsoft and Dropbox will provide our shared customers with flexible tools that put them at the center for the way they live and work today."

However, Office for iPad and its Android versions currently require a subscription to Office 365 for users to edit documents. Dropbox for Business customers will also need to subscribe for them to use the new features.

The update comes first to Dropbox and Dropbox for Business users on iOS and Android. However, the partnership means Dropbox will also have to make an app version for Windows Phone, which Microsoft says will be available "in the coming months". Office Online, which is free to all users, will also be integrating with Dropbox in 2015.